The present invention relates to a hazard avoidance system and, more particularly, a system for alerting and repelling animals posing a threat of vehicular collision.
Collisions between birds and aircraft occur wherever they share the same airspace. More than 5700 bird collisions or strikes with U.S. civil aircraft were reported in 2001 and it is estimated that 80% of bird strikes are not reported. The consequences of a collision between an aircraft and an animal depend, in part, on the sizes of the aircraft and the animal, the number of animals that are struck, and the location of the strike on the aircraft. However, a collision between an aircraft and an animal presents a serious hazard to the aircraft and more than 130 people have been killed worldwide since 1995 as result of collisions between birds and aircraft. The annual cost to U.S. civil aviation of collisions between birds and aircraft is estimated at $400 million per year.
While bird strikes are the major animal collision hazards for aircraft, mammals also pose a significant hazard. For example, bats present a significant in-flight hazard in some locales. Collisions between aircraft and coyotes, caribou, and elk have been reported and more than 500 collisions between deer and civilian aircraft were reported in the U.S. between 1990 and 2001.
Various methods are employed to reduce the hazard of animal collisions with aircraft. Since most birds fly at low altitudes, typically less than a few hundred feet, about 80% of bird strikes on civilian aircraft occur during takeoff and landing. Likewise, non-flying animals threaten aircraft during taxiing, take-off, and landing. As a result, several tactics to disperse or otherwise control animals are employed at airports. Typically, these methods employ selective hunting of problem species and non-lethal methods using frightening noises or sights. However, in many cases the problem species is a protected species and hunting is illegal. Non-lethal tactics can sometimes be used effectively in controlling transient migratory species, but usually the effectiveness of these techniques is short lived. Habitat modification, intended to deprive animals of food, shelter, space, and water, on an airport is the most effective longer term tactic for reducing the population of animals sharing space with aircraft that are taxiing, taking-off, and landing.
While the risk of collision to aircraft during taxiing, taking-off, and landing can be reduced by various techniques that modify the airport environment, these methods are only partially effective and have a limited geographic range. Although collisions occurring during the climb, cruise, and descent portions of a flight are less likely, they are likely to be more hazardous because they often involve large soaring birds or migrating flocks of waterfowl. To further reduce the potential of collisions between animals and aircraft throughout the flight, systems have been added to aircraft to warn the crew of the presence of birds and to encourage birds to avoid the path of the aircraft. For example, Steffen, U.S. Pat. No. 4,736,907, discloses an apparatus for preventing bird collisions comprising a plurality of lights that flash with continuously varying frequency. Increasing the frequency of light flashes has been found be more effective in causing an escape reaction in some birds and increasing the flash frequency for two separated light sources makes the vehicle appear to be moving closer at a high rate of speed increasing the acuteness of the escape reaction. A microprocessor-based control for the flashing lights permits storage of a plurality of flashing frequencies and cycles permitting the flight crew to select one of the light flashing routines appropriate to the speed of the plane when a collision hazard is anticipated.
A collision avoidance system enabling a plurality of light flashing patterns provides an opportunity to select a more effective response to a hazard. However, the flight crew must locate and identify a hazard to the aircraft and select a light flashing pattern with which to respond, often while engaged in tasks related to taking-off and landing. In the alternative, the flight crew can select a light flashing pattern, that is either manually initiated or automatically initiated by radar, and allow the system to operate until a collision indicates that the selected flashing pattern is ineffective.
What is desired, therefore, is a hazard avoidance system that can, with minimal manual intervention, select and initiate a light illumination routine that is effective to repel an anticipated collision threat.